CN118302240A

CN118302240A - Method and apparatus for reacting a feed with a cooled regenerated catalyst

Info

Publication number: CN118302240A
Application number: CN202280076732.1A
Authority: CN
Inventors: 约翰·J·塞内塔; A·M·布赫宾德; 潘卫; 沃尔夫冈·A·施皮克尔; R·A·约翰逊二世
Original assignee: UOP LLC
Current assignee: Honeywell UOP LLC
Priority date: 2021-11-02
Filing date: 2022-10-28
Publication date: 2024-07-05
Also published as: WO2023081596A1; US20230133426A1

Abstract

A fluidized catalytic reactor decouples catalyst regenerator temperature from catalyst reactor residence time. The regenerated catalyst is cooled prior to contacting the reactant feed. The regenerated catalyst may be cooled by heat exchange with an oxygen supply gas, spent catalyst or other material. The method and apparatus are particularly useful for fluidized endothermic catalytic reactions.

Description

Method and apparatus for reacting a feed with a cooled regenerated catalyst

Priority statement

The present application claims priority from U.S. provisional application No. 63/274,936 filed on month 11 and 2 of 2021, which is incorporated herein in its entirety.

Technical Field

The art relates to the reaction of a feed with a fluid catalyst. The art may specifically relate to reacting a feed with a fluid catalyst to catalyze an endothermic reaction.

Background

Light olefin production is critical to producing enough plastic to meet global needs. Alkane dehydrogenation (PDH) is a process in which light alkanes such as ethane and propane can be dehydrogenated to produce ethylene and propylene, respectively. Dehydrogenation is an endothermic reaction that requires external heat to drive the reaction to completion. Fluid Catalytic Cracking (FCC) is another endothermic process for producing essentially ethylene and propylene.

The dehydrogenation catalyst can utilize molecular sieves to incorporate a dehydrogenation metal, such as gallium, or an amorphous material. The catalyst must be sufficiently robust and sized to resist the attrition expected in a fluidized system. The FCC catalyst is typically a Y zeolite with an optional MFI zeolite to enhance propylene production.

In PDH and FCC reactions with fluidized catalyst, coke can be deposited on the catalyst while catalyzing the reaction. The catalyst may be regenerated in a catalyst regenerator by burning coke from the catalyst in the presence of oxygen. In some cases, the addition fuel may be combusted in the regenerator to increase the temperature of the regenerated catalyst. The thermally regenerated catalyst may then be transferred back to the reactor to catalyze the reaction. If insufficient heat is provided to drive the endothermic reaction, the conversion to the desired product will be lower than desired. The degree of conversion is therefore dependent on the amount of heat introduced into the reaction.

For a given temperature in the regenerator, additional heat may be provided to the reaction by increasing the catalyst circulation. Alternatively, additional heat may be provided by increasing the temperature of the regenerated catalyst at a given catalyst circulation rate. Increasing the regeneration temperature may be advantageous to increase the activity of the regenerated catalyst and reduce the costs associated with regeneration by minimizing the regenerator catalyst inventory and minimizing the excess air requirements. However, a disadvantage of increasing the regeneration temperature is that contacting the feed with regenerated catalyst at higher temperatures results in additional thermal cracking reactions. Catalytic reactions are more selective to the desired product than thermal cracking reactions. Care must be taken to maximize catalytic reactions relative to thermal cracking reactions. Another disadvantage of higher regenerated catalyst temperatures is that lower circulation rates increase the residence time of the catalyst in the reactor, as the catalyst inventory in the reactor remains unchanged. Longer reactor residence times result in increased catalyst deactivation.

Thus, there is a need for improved processes to allow regeneration at higher temperatures, which will minimize undesirable cracking reactions and longer catalyst residence times in the reactor.

Disclosure of Invention

The reactant stream is contacted with the cooled regenerated catalyst stream to produce a product gas stream. The spent catalyst is regenerated and cooled before being passed to the regenerator. The cooled regenerated catalyst stream enters the regenerator at a temperature that is lower than the temperature of the thermally regenerated catalyst stream. The cooling of the catalyst enables the catalyst residence time in the reactor to operate independently of the regenerator temperature.

Drawings

FIG. 1 is a schematic diagram of the method and apparatus of the present disclosure;

FIG. 2 is a schematic diagram of a method and apparatus of the alternative embodiment of FIG. 1;

FIG. 3 is a schematic diagram of a method and apparatus of the additional alternative embodiment of FIG. 1;

FIG. 4 is a schematic diagram of a method and apparatus of the further alternative embodiment of FIG. 1; and

Fig. 5 is a graph of propane conversion in a dehydrogenation reaction, for example, utilizing four different regeneration temperatures, versus run time in the reactor.

Definition of the definition

The term "in communication" refers to operatively permitting fluid flow between enumerated components, which may be characterized as "in fluid communication".

The term "downstream communication" means that at least a portion of the fluid flowing toward the body in the downstream communication may operably flow from the object with which it is in fluid communication.

The term "upstream communication" means that at least a portion of the fluid flowing from the body in the upstream communication may be operatively flowing toward the subject in fluid communication therewith.

The term "directly communicating" means that fluid flow from an upstream component enters a downstream component without passing through any other intervening vessels.

The term "indirect communication" means that fluid flow from an upstream component enters a downstream component after passing through an intervening container.

The term "bypass" means that the subject loses downstream communication with the bypass subject, at least within the scope of the bypass.

As used herein, the term "major" or "majority" means greater than 50%, suitably greater than 75%, and preferably greater than 90%.

Detailed Description

The catalyst residence time in the catalytic reactor may be an important parameter in determining catalyst deactivation. The catalyst residence time in the catalytic reactor is determined by equation 1:

Tr_cat ＝ W_cat/F_cat (1)

Where Tr _cat is the catalyst residence time, W _cat is the mass of catalyst in the reactor, and F _cat is the mass flow rate of the circulating catalyst. The Weight Hourly Space Velocity (WHSV) in the reactor is determined by equation 2:

WHSV ＝ F_f/W_cat (2)

where F _f is the mass flow rate of the feed to the reactor. Combining equations 1 and 2 into equation 3 provides a relationship between Tr _cat and WHSV:

tr _cat is therefore dependent on F _cat and WHSV required for the reaction.

The heat supplied to the reactor is given by equation 4:

Q_rxn ＝ F_cat*C_p*(T_regen-T_rxtr) (4)

Where Q _rxn is the heat supplied to the reactor, C _p is the specific heat constant of the catalyst, T _regen is the temperature of the regenerator, and T _rxtr is the temperature of the reactor. Rearranging equation 4 yields equation 5:

Combining equations 3 and 5 provides equation 6:

Thus, the catalyst residence time Tr _cat depends on the heat demand Q _rxn of the reaction and the temperature difference T _regen-T_rxtr between the reactor and the regenerator. Thus, the catalyst residence time in the reactor cannot be selected independently of the regenerator temperature.

The deactivation of the catalyst in the reactor depends on the catalyst residence time in the reactor. As catalyst accumulates coke and/or catalyst is deactivated by the deactivating atmosphere in the reactor, catalyst activity decreases in the reactor over time. For example, for propane dehydrogenation, the catalyst is deactivated by both blocking the active sites by coke and by exposure to the reducing conditions in the reactor. In FCC, the catalyst is deactivated by blocking the active sites by coke. The objective is to select an acceptable catalyst residence time in the reactor independent of other constraints.

Catalyst regeneration is controlled by regeneration conditions. The regeneration temperature T _regen is a key variable. It is generally sought to have a regeneration temperature as high as possible to facilitate complete regeneration of the catalyst and, if desired, to promote rapid combustion of the optional fuel gas fed to the regenerator to increase enthalpy. As the regeneration temperature increases, the catalyst circulation rate required to supply heat to the reactor decreases. The effect is an increase in residence time in the reactor and a decrease in catalyst activity due to catalyst deactivation over time in the reactor. We have found that the key to independently selecting acceptable catalyst residence time in the reactor is the ability to disengage the catalytic circulation rate from the temperature T _rxtr in the regenerator.

We have found a way to disengage the catalyst residence time in the reactor from the regeneration temperature. The process and apparatus can be operated in a regenerator at a fixed space velocity and constant conversion with short reactor catalyst residence time and high temperature. The method and apparatus achieve the desired effect by cooling the regenerated catalyst before it is fed to the reactor. For practical purposes, the heat recovered from the cooling of the regenerated catalyst should be recovered for use in the process. Most advantageously, heat should be recovered so as to have minimal impact on the fuel demand of the regenerator.

The teachings herein are applicable to any process that requires catalyst regeneration to provide heat to drive an endothermic catalytic reaction. The cooling of catalysts for exothermic reactors is well known; however, the invention herein demonstrates the surprising benefit of cooling the catalyst for a reactor containing an endothermic reaction. Alkane dehydrogenation (PDH) and Fluid Catalytic Cracking (FCC) are examples of endothermic processes. FCC catalysts are used to crack larger hydrocarbon molecules into smaller hydrocarbon molecules at about atmospheric pressure and a catalyst to oil ratio of 427 ℃ (800°f) to 538 ℃ (1000°f) and 5 to 30. PDH catalysts are used in dehydrogenation processes to catalyze the dehydrogenation of alkanes such as ethane, propane, isobutane and n-butane to alkenes such as ethylene, propylene, isobutylene and n-butene, respectively. The PDH method will be exemplarily described to illustrate the disclosed apparatus and method.

The conditions in the dehydrogenation reactor may include a temperature of 500 ℃ to 800 ℃, a pressure of 40kPa to 310kPa, and a catalyst to oil ratio of 5 to 100. The dehydrogenation reaction may be conducted in a fluidized manner such that a gas, with or without a fluidizing inert gas, which may contain the reactant alkane, is distributed to the reactor in a manner that lifts the dehydrogenation catalyst in the reactor vessel while catalyzing the dehydrogenation of the alkane. During the catalytic dehydrogenation reaction, coke is deposited on the dehydrogenation catalyst, resulting in a decrease in the activity of the catalyst. The dehydrogenation catalyst must then be regenerated.

An exemplary PDH reactor 10 is shown in fig. 1. The PDH reactor 10 may include two chambers: a reaction chamber 14 and a separation chamber 16. Feed line 8 may charge a reactant stream of the feed to reactor 10. The reactant stream may comprise primarily propane or butane, but other alkanes such as ethane may be present in the reactant stream along with or in lieu of other alkanes. Any feed distributor may distribute the reactant stream to reactor 10. A dome-shaped reactant distributor 20 may be utilized in the reaction chamber 14 of the reactor 10. The dome-shaped reactant distributor 20 receives the gaseous reactant stream through a nozzle in the top dome of the dome-shaped reactant distributor 20 and distributes the reactant stream to distribute the reactant stream across the cross-section of the reaction chamber 14. It is contemplated that other fluidization gases may also be used to promote fluidization in the reaction chamber 14. In one embodiment, the distributed reactant stream rises in the reaction chamber 14 and the reactor 10.

The recycled catalyst conduit 22 has an inlet end 21 located in the separation chamber 16 and an outlet constituting a first catalyst inlet 23, which in one embodiment is connectable to the reaction chamber 14. In one embodiment, the recycled catalyst conduit 22 conveys the first recycled spent catalyst stream that has not undergone regeneration from the separation chamber 16 to the reaction chamber 14 through an outlet and a first catalyst inlet 23. The first catalyst inlet 23 provides spent catalyst to the reaction chamber 14. The recycled spent catalyst is fed to the reactor 10 through a first catalyst inlet 23 which is the outlet of the recycled catalyst conduit 22. The first catalyst inlet 23 may be housed in the first reaction chamber 14.

The second catalyst inlet 25 delivers a second catalyst stream to the reactor 10. The regenerated catalyst conduit 26 has an inlet 27 in upstream communication with the second catalyst inlet 25. The inlet end of regenerated catalyst conduit 26 is connected to regenerator 60. Regenerated catalyst conduit 26 conveys the second regenerated catalyst stream from regenerator 60 to second catalyst inlet 25. The regenerated catalyst conduit may be in downstream communication with the regenerator 60. A second catalyst inlet 25 is contained in the reaction chamber 14 and provides regenerated catalyst to the reaction chamber. The reactant stream is contacted with the second catalyst stream and the first catalyst stream in reaction chamber 14. The second catalyst inlet 25 may be spaced apart from and may be above the first catalyst inlet 23.

In reaction chamber 14, the reactant stream is contacted with the second and first catalyst streams mixed together and the reactant alkane undergoes endothermic conversion to an olefin, typically propane to propylene. The reactant stream and the first and second catalyst streams rise in the reaction chamber 14 of the reactor 10, pushed by the reactant stream continuously entering the reactor.

At interface 28, the fluid dynamics transitions from a dense phase of catalyst below the transition to a fast fluidization flow state. The catalyst density in the dense phase of the catalyst is at least 200kg/m ³(12.5lb/ft³); and a catalyst density in the fast fluidization flow regime of at least 100kg/m ³(6.3lb/ft³). The superficial flow rate of the reactant stream in the reaction chamber 14 and the first and second catalyst streams will typically be at least 0.9m/s (3 ft/s), suitably at least 1.1m/s (3.5 ft/s), preferably at least 1.4m/s (4.5 ft/s) to 2.1m/s (7 ft/s) to provide a fast fluidization flow regime. The reactant gas and catalyst rise in a fast fluidized flow regime, wherein the catalyst can slide relative to the gas and the gas can take an indirect upward trajectory.

The dehydrogenation catalyst selected should minimize cracking reactions and facilitate dehydrogenation reactions. Catalysts suitable for use herein include active metals that may be dispersed in a porous inorganic support material such as silica, alumina, silica-alumina, zirconia or clay. Exemplary embodiments of the catalyst include alumina or silica-alumina containing gallium, noble metals, and alkali or alkaline earth metals.

The catalyst support comprises a support material, a binder and optionally a filler material to provide physical strength and integrity. The support material may comprise alumina or silica-alumina. Silica sol or alumina sol may be used as the binder. Alumina or silica-alumina typically comprises alumina in the gamma, theta and/or delta phase. The nominal diameter of the catalyst support particles may be from 20 microns to 200 microns with an average diameter of from 50 microns to 150 microns. Preferably, the surface area of the catalyst support is from 85m ²/g to 140m ²/g.

The dehydrogenation catalyst can comprise a dehydrogenation metal on a support. The dehydrogenation metal may be one or a combination of transition metals. The noble metal may be a preferred dehydrogenating metal, such as platinum or palladium. Gallium is an effective metal for alkane dehydrogenation. The metal may be deposited on the catalyst support by impregnation or other suitable methods, or may be included in the support material or binder during catalyst preparation.

The acid functionality of the catalyst should be minimized to prevent cracking and to facilitate dehydrogenation. Alkali metals and alkaline earth metals may also be included in the catalyst to reduce the acidity of the catalyst. Rare earth metals may be included in the catalyst to control the activity of the catalyst. Metals may be incorporated into the catalyst at concentrations of 0.001 wt% to 10 wt%. In the case of noble metals, it is preferable to use 10 parts per million by weight (ppm) to 600ppm by weight of noble metals. More preferably, from 10ppm to 100ppm by weight of noble metal is preferably used. The preferred noble metal is platinum. Gallium should be present in the range of 0.3 to 3 wt%, preferably 0.5 to 2 wt%. The alkali metal and alkaline earth metal are present in the range of 0.05 wt% to 1 wt%.

The reactant stream lifts the first catalyst stream mixed with the second catalyst stream upwardly in the reaction chamber while the alkane is converted to olefin in the presence of a dehydrogenation catalyst that gradually becomes spent due to agglomeration of coke deposits on the catalyst. A fluidizing inert gas may be distributed to the reaction chamber to help lift the mixture of catalyst and reactants upward in the reaction chamber 14. The reactant gas is converted into a product gas while rising in the reaction chamber 14. The blend of gas and catalyst rises from the reaction chamber 14 through a frustoconical transition zone 30 to a transport riser 32 having a diameter smaller than the diameter of the reaction chamber 14. The blend of gas and catalyst is accelerated in a narrower transport riser 32 and discharged from a primary catalyst separator 34 into the separation chamber 16. Primary catalyst separator 34 may be a riser termination device that utilizes horizontal, centripetal acceleration to separate spent catalyst from product gas. The arcuate conduit of the primary catalyst separator 34 directs the product gas and catalyst mixture away from the riser 32 in a generally horizontal angular direction to centripetally accelerate, thereby causing the denser catalyst to move outwardly under the force of gravity. The catalyst loses angular momentum and falls into the lower catalyst bed 36 depicted by the upper boundary. The lighter gases rise in the separation chamber 16 and enter the cyclones 38, 40. The cyclones 38, 40 may include a first cyclone stage and a second cyclone stage to further remove catalyst from the product gas. The product gas is ducted to a plenum 42 from which the product gas is discharged from the reactor 10 through a product outlet 44 in the product line. The superficial gas flow rate in the transport riser 32 will be 12m/s (40 ft/s) to 20m/s (70 ft/s) and have a density of 64kg/m ³(4lb/ft³ to 160kg/m ³(10lb/ft³, constituting a lean catalyst phase.

The catalyst separated from the product gas by the primary catalyst separator 34 falls into a dense catalyst bed 36. In one aspect, the primary cyclone 38 may collect the product gas from the separation chamber 16 and transport the product gas separated from the catalyst to the secondary cyclone 40 to further separate the catalyst from the product gas, and then direct the secondarily purified product gas to the plenum 42. The catalyst separated from the product gas in the cyclones 38, 40 is distributed through the diplegs into the dense catalyst bed 36. At this time, the catalyst separated in the separation chamber 16 is considered as a spent catalyst because deposits of coke agglomerate thereon. The spent catalyst stream, taken from the spent catalyst collected in dense bed 36 in separation chamber 16, is transported in spent catalyst conduit 18 to catalyst regenerator 60 to combust coke from the catalyst to regenerate and heat the dehydrogenation catalyst.

The recycle catalyst stream is taken from spent catalyst collected in dense bed 36 in separation chamber 16 and enters recycle catalyst conduit 22 through inlet 21. The recycle catalyst stream of spent catalyst is recycled back to the first catalyst inlet 23 in the reaction chamber 14 of the reactor 10 in the recycle catalyst conduit 22. The recycled catalyst stream of spent catalyst is not regenerated prior to being returned to the reaction chamber 14.

The separation chamber 16 may include a disengagement tank 46 surrounding the upper end of the riser 32 and the primary separator 34. The vertical wall 47 of the disengagement tank 46 is spaced from the housing 48 of the disengagement chamber to define an annular portion 49. The immersed legs of the cyclones 38 and 40 may be located in the annular portion 49. The disengaging tank 46 serves to limit the travel of the product gas out of the primary separator 34 so as to reduce the time the product gas spends in the reactor 10, thereby mitigating non-selective cracking reactions to undesired products. The top of the disengaging tank 46 may be hemispherical and feed a gas recovery conduit 50 that transports the product gas to a conduit 52 that is directly conduit or connected to the primary cyclone 38. The direct conduit connection from the disengaging tank 46 to the primary cyclone 38 also prevents product gas from escaping in the larger volume of the reactor vessel, where excessive residence time may occur to allow for non-selective cracking. Windows in the lower section of the wall 48 of the disengaging tank 46 allow catalyst in disengagement to enter the recycled catalyst conduit 22 or the regeneration conduit 18. A quench fluid such as condensed product liquid, cooled recycle gas, or even cold catalyst may be injected into the product gas through quench nozzle 54 to cool the product gas below the cracking temperature to limit non-selective cracking. The quench fluid is advantageously injected into a gas recovery conduit 50 that directs the separated product gas to a narrow location. The gas recovery conduit 50 communicates downstream with a primary catalyst separator 34 that separates a substantial portion of the spent catalyst from the product gas. The spent catalyst from the primary separation bypasses the quench to retain heat in the catalyst. The product gas separated from the majority of the catalyst subjects the reduced amount of material to quenching, requiring less quench fluid to achieve sufficient cooling to reduce the temperature of the product gas below the cracking temperature.

Spent catalyst is transported to a catalyst regenerator vessel 60 to regenerate spent catalyst and burn coke, if present. The catalyst regenerator vessel 60 includes a combustion chamber 62 that may be a lower chamber and a separation chamber 64 that may be an upper chamber. The combustion chamber 62 may include a mixing chamber 66 that mixes the catalyst flow and distributes the gas to the catalyst. In the separation chamber 64, the regenerated catalyst is separated from the flue gas generated in the combustion chamber 62.

In an exemplary embodiment, the regenerator vessel 60 includes a mixing chamber 66. Mixing chamber 66 may be located at the lower end of combustion chamber 62 and regenerator vessel 60. The mixing chamber 66 may be connected to the outlet end 19 of the spent catalyst conduit 18, which serves as an inlet to the mixing chamber. The spent catalyst standpipe 18 transports spent catalyst from the dehydrogenation reactor 10 through a control valve to a catalyst regenerator vessel 60. In some cases, the spent catalyst standpipe 18 may transport catalyst to the regenerator vessel 60 via a spent catalyst stripper (not shown). The mixing chamber 66 may also include a regenerated catalyst conduit inlet 67 from a regenerated catalyst standpipe 68 that serves as an outlet for the regenerated catalyst conduit. The heated regenerated catalyst from the separation chamber 64 may be transported back to the catalyst regenerator vessel 60 through a control valve via a recycled regenerated catalyst conduit 68 to further heat the catalyst in the regenerator vessel 60 by contact with the hot regenerated catalyst.

The outlet end 19 of the spent catalyst conduit discharges the spent catalyst stream from the spent catalyst standpipe 18 into the mixing chamber 66, and the regenerated catalyst conduit inlet 67 discharges a recycled portion of the regenerated catalyst from the regenerated catalyst conduit 68 into the mixing chamber 66. The mixing chamber 66 receives the spent catalyst stream and the hot regenerated catalyst stream and mixes them together to provide a mixture of catalysts. Upon mixing, the hotter regenerated catalyst heats the cooler spent catalyst, thereby providing a heated catalyst mixture.

In one embodiment, a mixing baffle 70 may be positioned within the mixing chamber 66 to facilitate mixing between spent catalyst and regenerated catalyst. The mixing baffle 70 may comprise a capped cylinder having an opening opposite the catalyst inlet 19 or 67.

An oxygen supply gas line 72 provides an oxygen supply gas into the mixing chamber 66. The oxygen supply gas from the oxygen supply gas line 72 contains oxygen necessary for combustion. The oxygen supply gas may also fluidize the catalyst within the mixing chamber 66 and lift the catalyst from the mixing chamber up into the combustion chamber 62.

The coke on the spent catalyst may not be sufficient to generate sufficient enthalpy from the combustion to drive the endothermic reaction in the dehydrogenation reactor. In some cases, the catalyst may be deactivated by mechanisms other than coke deposition and oxidation is required to regenerate activity, even with very little or no detectable coke on the spent catalyst. In addition, higher regeneration temperatures allow for more recovery of catalyst activity. Accordingly, supplemental fuel gas may be added to the mixing chamber 66 in the regenerator vessel 60 to provide additional combustion enthalpy to drive the endothermic reaction in the dehydrogenation reactor and fully restore catalyst activity. Fuel gas from fuel gas line 74 may be provided to combustion chamber 62 through mixing chamber 66. The two gas streams lift the catalyst in the combustion chamber 62 into the separation chamber 64.

The fuel gas is combusted with oxygen in the oxygen supply gas in the presence of the catalyst to provide a heated regenerated catalyst. In addition, coke on the catalyst is also combusted from the catalyst along with oxygen in the oxygen supply gas to provide a regenerated catalyst. The combustion of coke and fuel gas produces flue gas. In one embodiment, the fuel gas and the coke on the catalyst are combusted together in the same vicinity, beginning in the mixing chamber 66 and then in the combustion chamber 62.

The superficial gas flow rate in the mixing chamber 66 may be 0.9m/s (3 ft/s) to 5.4m/s (18 ft/s) and the catalyst density may be 112kg/m ³(7lb/ft³) to 400kg/m ³(25lb/ft³), preferably 48kg/m ³(3lb/ft³) to 288kg/m ³(18lb/ft³), constituting a dense catalyst phase in the mixing chamber 66.

In an exemplary embodiment, air is used as the oxygen supply gas because air is readily available and provides sufficient oxygen for combustion. 10kg to 15kg of air is required per kg of coke burned off the spent catalyst. Exemplary regeneration conditions in the combustion chamber 62 include temperatures of 690 ℃ to 800 ℃, preferably 705 ℃ to 750 ℃, and pressures of 6.9kPa (gauge) (1 psig) to 450kPa (gauge) (70 psig).

The catalyst, fuel gas and oxygen supply gas in the combustion chamber 62 rise, while coke is burned from the catalyst and the fuel gas burns to regenerate and heat the catalyst and produce flue gas. The flow regime may be a fast fluidization flow regime, in which the catalyst may slide relative to the gas, and the gas may take an indirect upward trajectory. The superficial flow rate of the gas rising in the combustion chamber 62 is preferably 1.5m/s (5 ft/s) to 6m/s (20 ft/s), and preferably 2.1m/s (7 ft/s) to 5.4m/s (18 ft/s) to provide a fast fluidization flow regime. The catalyst density in the lean catalyst phase in the combustion chamber 62 will be 16kg/m ³(1lb/ft³) to 192kg/m ³(12lb/ft³).

The blend of gas and catalyst rises from the combustion chamber 62 through the frustoconical transition section 76 to a riser 80 having a diameter smaller than the major diameter of the combustion chamber 62. The blend of gas and catalyst is accelerated in a narrower riser 80 and discharged from riser termination device 82 into separation chamber 64. Transition section 76, riser 80, and riser termination device 82 are considered to be part of combustion chamber 62. Riser termination device 82 may utilize centripetal acceleration to separate regenerated catalyst from the flue gas. The superficial gas flow rate in riser 80 will be 6m/s (20 ft/s) to 15m/s (50 ft/s) and constitute the lean catalyst phase.

Regenerated catalyst separated from the flue gas by riser termination device 82 falls into dense catalyst bed 84. The catalyst separation chamber 64 may include one or more regenerator cyclones 86 or other solid/gaseous separator devices to separate regenerated catalyst that is still entrained in the flue gas. In one aspect, the primary cyclone 86 may collect flue gas from the separation chamber 64 and convey the flue gas separated from the catalyst to a secondary cyclone 88 to further separate regenerated catalyst from the flue gas, and then direct the secondarily purified flue gas to a plenum 90. Flue gas is discharged from the regenerator vessel 60 through an outlet 62 in a discharge line. Regenerated catalyst separated from the flue gas in cyclones 86, 88 is distributed through the diplegs into dense catalyst bed 84.

The fluidization gas stream may be distributed into the separation chamber 64 to fluidize the regenerated catalyst in the dense catalyst bed 84. The fluidizing gas may be an oxygen supplying gas (such as air used in the combustion chamber 62), or it may be an inert gas (such as steam or nitrogen).

The return portion of the regenerated catalyst collected in the dense bed 84 of the catalyst separation chamber 64 may be transported back to the dehydrogenation reactor in the return regenerated catalyst standpipe 26 in preparation for catalytic dehydrogenation reactions. The return portion of regenerated catalyst may exit the separation chamber 64 through the inlet end 27 of the regenerated catalyst conduit 26 to enter the return regenerated catalyst standpipe 26.

The recycled portion of the regenerated catalyst collected in the dense bed 84 of the catalyst separation chamber 64 may be recycled back to the combustion chamber 62 of the regenerator vessel 60 in the recycled regenerated catalyst standpipe 68 via the mixing chamber 66. The regenerated catalyst is hotter and has a lower coke concentration than the spent catalyst fed to the regenerator vessel in the spent catalyst standpipe 18. The regenerated catalyst is returned to the reactor 10 at least partially in the regenerated catalyst conduit 26.

Regenerated catalyst conduit 26 has an inlet end 27 connected to regenerator 20 in separation chamber 25 through which regenerated catalyst from the regenerator is transported to reactor 10. To disengage the regenerated catalyst temperature from the catalyst residence time in the reactor 10, the regenerated catalyst in the regenerated catalyst conduit 26 may be cooled in a catalyst cooler 92. The hot regenerated catalyst is fed from regenerated catalyst conduit 26 to catalyst cooler 92 through outlet end 93 of the regenerated catalyst conduit. The outlet end 93 may be connected to a catalyst cooler 92. The catalyst cooler 92 may be in downstream communication with the regenerated catalyst conduit 26. A gas stream in line 94, such as an oxygen supply gas, may be fed to the catalyst cooler 92 through coil 95 in the catalyst cooler 92 to indirectly exchange heat with the thermally regenerated catalyst. The cooled regenerated catalyst exits the catalyst cooler 92 through an inlet end 97 of a cooled catalyst conduit 96. The inlet end of the cooled catalyst conduit 96 may be connected to the catalyst cooler 92. The cooled catalyst conduit may be in downstream communication with a catalyst cooler 92. The cooled regenerated catalyst conduit delivers a cooled regenerated catalyst stream to the reactor 10 through the outlet end 25 at a flow rate controlled by a control valve thereon. The outlet end 25 may be connected to the reactor 10. Reactor 10 may be in downstream communication with cooled catalyst conduit 96. The cooled regenerated catalyst stream is fed to reactor 10 through inlet 25 at a temperature lower than the temperature of the hot regenerated catalyst stream exiting regenerator 60 through inlet end 27. The oxygen supply gas in line 94 is heated by heat exchange with the hot regenerated catalyst from line 26 and exits catalyst cooler 92 in line 98. The heated oxygen supply gas may be fed to the regenerator 60 to meet the oxygen supply gas demand, possibly in combination with the oxygen supply gas in the oxygen supply gas line 72. Heating the oxygen supply gas prior to entering the regenerator promotes combustion of coke deposits on the catalyst and combustion of the fuel gas. The oxygen supply gas in line 94 may be heated from 450 ℃ to 660 ℃ and the hot regenerated catalyst stream may be cooled from 20 ℃ to 50 ℃. The heated oxygen supply gas may be used with heating other streams (such as fuel gas or steam) to provide sufficient catalyst cooling.

In one embodiment, regenerated catalyst conduit 26 may be provided with a bypass line 100 having a control valve thereon for adjusting the flow rate of catalyst to catalyst cooler 92 independent of the flow rate of oxygen supply gas to the catalyst cooler in line 94.

The catalyst cooler 92 may also be used to generate steam, superheated steam, or provide heat to another region of the process while cooling the catalyst to be fed to the reactor 10 in a cooled catalyst conduit 96 to enable higher catalyst circulation rates independent of catalyst regeneration conditions.

Fig. 2 shows an alternative embodiment of a regenerator 60' that employs fuel gas to cool the thermally regenerated catalyst. Elements in fig. 2 having the same configuration as in fig. 1 will have the same reference numerals as in fig. 1. Elements in fig. 2 having a different configuration than the corresponding elements in fig. 1 have the same reference numerals but are indicated by a prime ('). The configuration and operation of the embodiment of fig. 2 is essentially the same as in fig. 1, with the following exceptions.

The hot regenerated catalyst is fed from regenerated catalyst conduit 26 to catalyst cooler 92 through outlet end 93 of the regenerated catalyst conduit. The fuel gas stream comprising light hydrocarbons and/or hydrogen in line 94' can be fed to the catalyst cooler 92 through coil 95 in the catalyst cooler 92 to indirectly exchange heat with the thermally regenerated catalyst. The cooled regenerated catalyst exits the catalyst cooler 92 through outlet 97 into a second regenerated catalyst conduit 96. The second regenerated catalyst conduit delivers a cooled regenerated catalyst stream to reactor 10 through inlet 25 at a flow rate controlled by a control valve thereon. The cooled regenerated catalyst stream is fed to reactor 10 through inlet 25 at a temperature lower than the temperature of the hot regenerated catalyst stream exiting regenerator 60 through inlet end 27 of regenerated catalyst conduit 26. The fuel gas in line 94' is heated by heat exchange with the hot regenerated catalyst from line 26 and exits catalyst cooler 92 in line 98. The heated fuel gas may be fed to the regenerator 60 to meet fuel gas requirements, possibly in combination with the fuel gas in the fuel gas line 74'. Heating the fuel gas prior to entering the regenerator facilitates combustion of the fuel gas because the fuel gas does not need to be fully heated in the regenerator. The fuel gas in line 94 may be heated from 500 ℃ to 700 ℃, and the hot regenerated catalyst stream may be cooled from 2 ℃ to 10 ℃. Heating the fuel gas may be used with heating other streams (such as fuel gas or steam) to provide sufficient catalyst cooling.

Fig. 3 shows an alternative embodiment of a reactor 10 "and a regenerator 60" for cooling the thermally regenerated catalyst by heat exchanging it with spent catalyst. Elements in fig. 3 having the same configuration as in fig. 1 will have the same reference numerals as in fig. 1. Elements in fig. 3 having a different configuration than the corresponding elements in fig. 1 will have the same reference numerals but are indicated by double prime ("). The configuration and operation of the embodiment of fig. 3 is essentially the same as in fig. 1, with the following exceptions.

The catalyst cooler 92 "includes a catalyst heat exchanger in downstream communication with the regenerated catalyst conduit 26" and the spent catalyst conduit 18 ". Catalyst cooler 92 "has a first side in communication with regenerated catalyst conduit 26" and cooled catalyst conduit 96 ". The outlet end 93 "of the regenerated catalyst conduit 26" is connected to the manifold 102 of the catalyst cooler 92 ". Manifold 102 receives hot regenerated catalyst from regenerated catalyst conduit 26 "and distributes the hot regenerated catalyst to a plurality of catalyst tubes 104 or channels including a first side of catalyst cooler 92". The collector 108 receives catalyst from the tubes 104. The inlet end 97 "of the cooled catalyst conduit 96" is connected on a first side to the catalyst cooler 92 "to receive cooled catalyst from the collector 108.

A second side of the catalyst cooler 92 "may be in communication with the spent catalyst conduit 18" and the heated catalyst conduit 106. The spaces 110 between the tubes 104 receive spent catalyst from the spent catalyst conduit 18 ". The catalyst cooler 92 "is in downstream communication with the spent catalyst conduit 18". Specifically, the outlet end 17 of the spent catalyst conduit 18 "is connected to the catalyst cooler 92" on a second side, and the inlet end 105 of the heated catalyst conduit 106 is connected to the catalyst cooler 92 "on a second side.

Hot regenerated catalyst from regenerated catalyst conduit 26 "exits outlet end 93" and enters manifold 102 "and is distributed to catalyst tubes 104 on a first side of catalyst cooler 92". Spent catalyst from the spent catalyst conduit 18 "exits the outlet end 17 and enters the space 110" between the tubes 104 on the second side of the catalyst cooler 92". Heat is indirectly exchanged from regenerated catalyst to spent catalyst across the tubes 104, heating the spent catalyst and cooling the regenerated catalyst. The heated spent catalyst exits the space 110 between the tubes 104 through the inlet end 105 of the heated catalyst conduit 106 and the cooled regenerated catalyst is collected in the collector 108 and exits the catalyst cooler 92 "through the inlet end 97" of the cooled catalyst conduit 96 ". Cooled catalyst from cooled catalyst conduit 96 "is conveyed to reactor 10 through outlet end 25 and the heated spent catalyst stream is conveyed to regenerator 60 through outlet end 19 of heated catalyst conduit 106. The catalyst cooler 92 "may be in downstream communication with the spent catalyst conduit 18" and the regenerator 60 may be in downstream communication with the heated catalyst conduit 106. The spent catalyst stream in the spent catalyst conduit 18 "may be heated from 20 ℃ to 60 ℃ and the hot regenerated catalyst stream in the regenerated catalyst conduit 26 may be cooled from 20 ℃ to 60 ℃.

Adjusting the flow rate of the hot regenerated catalyst in conduit 26 "to catalyst cooler 92" may be used to control the cooling rate of the hot regenerated catalyst. To this end, regenerated catalyst bypass conduit 112 has an inlet end 111 connected to regenerated catalyst conduit 26 "and an outlet end 113 connected to cooled catalyst conduit 96". Adjusting the rate of hot regenerated catalyst by bypassing a portion of the hot regenerated catalyst in hot regenerated catalyst conduit 26 "around catalyst cooler 92 into the bypass conduit with a control valve on bypass conduit 112 controls the temperature of regenerated catalyst entering reactor 10" through outlet end 25 of cooled catalyst conduit 96 ". Bypassing more hot regenerated catalyst in regenerated catalyst conduit 26 "through regenerator bypass conduit 112 to mix with cooled catalyst in cooled catalyst line 96" will increase the temperature of the cooled regenerated catalyst in the cooled catalyst line. Bypassing less hot regenerated catalyst in regenerated catalyst conduit 26 "through regenerator bypass conduit 112 to mix with cooled catalyst in cooled catalyst line 96" will reduce the temperature of the cooled regenerated catalyst in the cooled catalyst line.

Adjusting the flow rate of spent catalyst in conduit 18 "to catalyst cooler 92" may also be used to control the cooling rate of the thermally regenerated catalyst. To this end, spent catalyst bypass conduit 116 has an inlet end 115 connected to regenerated catalyst conduit 26 "and an outlet end 117 connected to heated catalyst conduit 106. Adjusting the rate of spent catalyst by bypassing a portion of the spent catalyst in the bypass spent catalyst conduit 18 "around the catalyst cooler 92" into the bypass conduit 116 may control the temperature of regenerated catalyst entering the reactor 10 "through the outlet end 25 of the cooled catalyst conduit 96". Bypassing more spent catalyst in the spent catalyst conduit 18 "through the spent bypass conduit 116 reduces the cooling of the hot regenerated catalyst in the hot regenerated catalyst conduit 26" to increase the temperature of the cooled regenerated catalyst in the cooled catalyst conduit 96 ". Bypassing less spent catalyst in spent catalyst conduit 18 "through spent bypass conduit 116 will provide more cooling in cooled catalyst line 96" to reduce the temperature of the cooled regenerated catalyst in the cooled catalyst line.

The fluidization gas line 130 may feed the distributor on a first side of the catalyst heat exchanger 92 "and/or on a second side of the catalyst heat exchanger. The degree of heat transfer may be adjusted by varying the degree of fluidization of the catalyst on either or both sides of the catalyst heat exchanger 92 ". Increasing the degree of fluidization will increase heat transfer between the catalyst streams, while decreasing the degree of fluidization will decrease heat transfer between the catalyst streams.

Fig. 4 shows an alternative embodiment of a reactor 10 for cooling a thermally regenerated catalyst by mixing it with cooled spent catalyst. Elements in fig. 4 having the same configuration as in fig. 1 will have the same reference numerals as in fig. 1. Elements in fig. 4 having a different configuration than the corresponding elements in fig. 1 will have the same reference numerals but are denoted by asterisks. The configuration and operation of the embodiment of fig. 4 is substantially the same as in fig. 1, with the following exceptions.

The recycle catalyst stream of spent catalyst taken from inlet end 21 in recycle catalyst conduit 22 may be cooled in catalyst cooler 92 from which it enters through outlet end 119 of the recycle catalyst conduit. The catalyst cooler 92 may cool the recycle catalyst stream by heat exchange with a stream of oxygen supply gas or fuel gas intended for the regenerator, regenerated catalyst, water or alkane feed intended for the reactor 10. In fig. 4, the reactant stream of the alkane feed in line 6 is preheated by heat exchange with the recycle catalyst stream of spent catalyst in recycle catalyst conduit 22. In heat exchange, catalyst cooler 92 cools the recycle catalyst stream by heat exchange with the cooler reactant stream in line 6 to produce a preheated reactant stream in feed line 8. The cooled recycle catalyst stream may exit the catalyst cooler 92 through the inlet end 121 of the cooled catalyst conduit 120 and be fed to the reactor 10 through the outlet end 23 of the cooled catalyst conduit.

The hot regenerated catalyst stream entering the reactor 10 from regenerated catalyst conduit 26 through inlet end 25 is cooled as it mixes with the cooled recycled catalyst stream entering through outlet end 23 of cooled catalyst conduit 120 to provide a cooled regenerated catalyst stream in the catalyst bed represented by interface 28. The cooled regenerated catalyst stream is contacted with a preheated reactant stream from feed line 8.

The foregoing disclosure describes a method and apparatus that enables the regenerator 60 to operate at an optimal temperature for catalyst regeneration while independently operating the reactor 10 at an optimal catalyst reactor residence time.

The alkane feed in line 6 can be heated 300 ℃ to 500 ℃ and the hot recycle catalyst stream can be cooled to 50 ℃ to 100 ℃.

The catalyst cooler 92 may also be used to generate steam, superheated steam, or provide heat to another region of the process while cooling the catalyst to be returned to the reactor 10 in a cooled catalyst conduit 120 to enable higher catalyst circulation rates independent of catalyst regeneration conditions.

All of the catalyst coolers 92, 92', 92 "and 92" may be shell and tube heat exchangers, sleeve heat exchangers, plate heat exchangers, or any other type of heat exchanger.

Examples

The catalyst was prepared by incipient wetness impregnation of aqueous solutions of gallium nitrate, potassium nitrate and platinum tetrammine nitrate on microspheroidal spray-dried alumina containing 1% sio ₂. The BET surface area of the catalyst support was measured by nitrogen adsorption and was 134m ²/g. The impregnation was followed by calcination in air at 750 ℃ for 4 hours. The catalyst contained 0.0076% pt, 1.56% ga, 0.26% k, 0.5% si (by weight) as measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The catalyst was white in appearance. The carbon and nitrogen content was measured by CHN method D5291. The carbon content of the fresh catalyst was 0.07 wt% approaching the detection limit of 0.05 wt% (probably due to adsorbed carbonate). Nitrogen was undetectable (limit of detection 0.05 wt%).

Long term aging of the catalyst was simulated by cycling the catalyst between reactor conditions and regenerator conditions as follows:

Starting: 2cm ³ of catalyst were loaded into a quartz tube reactor. The catalyst was heated to 120 ℃ under nitrogen and held for 30 minutes. The temperature was raised to 720 ℃ at 10 ℃/min under nitrogen and regeneration conditions were started.

And a regeneration step: the temperature was raised to 720℃at 10℃per minute under nitrogen. The gas composition was changed from nitrogen to 5% O ₂、24.2％H₂ O, balance N ₂ (by volume) and flowed for 2 minutes at a gas flow rate of 15 standard cm ³ per cm ³ catalyst per minute. The gas composition was changed back to nitrogen, the temperature was maintained for 0.5 minutes, and cooling was started.

The reaction steps are as follows: the sample was cooled to 620 ℃ at 13 ℃/min under nitrogen. The gas composition was changed from nitrogen to propane. Propane was flowed at a gas flow rate of 7.5cm ³ per cm ³ of catalyst per minute for 2 minutes. The gas composition was changed back to nitrogen, the temperature was maintained for 0.5 minutes, and heating of the regeneration step was started.

630 Regeneration cycles were completed and additional regenerations were performed at the end of the program. The catalyst was cooled under nitrogen and taken out for further testing.

We tested the activity of the aged platinum-gallium catalysts in propane dehydrogenation test equipment at different regeneration temperatures. We simulated catalyst regeneration for 1 minute at various temperatures in an environment of 25 wt% water, 5wt% oxygen, and the balance nitrogen. 150mg of the aged catalyst was loaded between quartz tampons in a quartz tube reactor having an inner diameter of 3.85 mm. Inert alpha alumina spheres are loaded below the catalyst bed to minimize thermal cracking. The reactor effluent composition was analyzed by transmitted infrared spectroscopy to identify propane, propylene, ethane, ethylene and methane products, with data collected every 7 seconds. The effluent of the infrared analyzer is directed to a gas chromatograph that is used to occasionally analyze the product stream and to check the accuracy of the infrared analyzer for an actual product stream.

The catalyst was dried under nitrogen and maintained at 120 ℃ for 30 minutes, then heated under nitrogen to regeneration temperatures of 690 ℃, 705 ℃, 720 ℃ and 735 ℃. The catalyst was then exposed to a dry gas mixture consisting of 5 mole% O ₂ and the balance nitrogen, where the dry gas flow of O ₂ and nitrogen was 15 standard cm ³/min, mixed with 25 mole% steam generated by evaporation of water fed from the pump. The exposure to the steam/O ₂/nitrogen mixture was continued for 1 minute, at which point it was stopped and replaced with dry nitrogen.

After this pretreatment, the catalyst was cooled to 620 ℃ under dry nitrogen. The catalyst was then exposed to 2 mole% H ₂ O in nitrogen generated by bubbling nitrogen through a saturator in a temperature controlled bath. The wet pretreatment of the catalyst was maintained for 60 minutes. The nitrogen/H ₂ O mixture was then stopped and replaced with 9 standard cm ³/min propane and 1.5 standard cm ³/min hydrogen feed. The feed was flowed for 2 minutes after which the gas composition was converted to nitrogen. The regeneration temperature was raised to 690 ℃, 705 ℃, 720 ℃ or 735 ℃ for regeneration. During regeneration, the catalyst was then exposed to a dry gas mixture consisting of 5 mole% O ₂ with the balance nitrogen, where the dry gas flow of O ₂ and nitrogen was 15 standard cm ³/min, mixed with 25 mole% steam generated by evaporation of water fed from the pump. The exposure to the steam/O ₂/nitrogen mixture was continued for 1 minute, at which point it was stopped and replaced with dry nitrogen. The catalyst was then cooled to 620 ℃ for the next reaction step. The O ₂/propane cycle was repeated four times.

For experiments with four different regeneration temperatures, the propane conversion at or near 0.54 minutes in the fourth cycle is shown in table 1. The conversion is shown in figure 5 with the run time representing the reactor residence time. The legend to fig. 5 is provided in the last column of table 1. Higher regeneration temperatures result in higher propane conversion in subsequent reaction cycles. At shorter reactor residence times in the reactor, the conversion corresponding to activity is higher.

TABLE 1

Regeneration temperature, DEG C	Propane conversion	The designation of FIG. 5
			690	41.52	*
705	44.66	◆
			720	47.00^a	●
735	48.32	x

^a There were no data points at 0.54 minutes, so the average conversion at 0.44 minutes and 0.66 minutes was reported.

Detailed description of the preferred embodiments

While the following is described in conjunction with specific embodiments, it is to be understood that the description is intended to illustrate and not limit the scope of the foregoing description and the appended claims.

A first embodiment of the present disclosure is a process for contacting a reactant stream with a regenerated catalyst, the process comprising: charging a reactant stream to a reactor; contacting the reactant stream with a cooled regenerated catalyst stream to produce a product gas stream and a spent catalyst; passing the spent catalyst stream to a regenerator; regenerating the spent catalyst stream by combustion in the regenerator to provide a hot regenerated catalyst stream and a flue gas stream; cooling the catalyst stream; and passing the regenerated catalyst stream to the reactor. An embodiment of the disclosure is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising cooling the thermally regenerated catalyst stream by heat exchange. An embodiment of the disclosure is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising cooling the thermally regenerated catalyst stream by heat exchange with air. An embodiment of the disclosure is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising returning heated air from the heat exchange to the regenerator. An embodiment of the disclosure is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising cooling the hot regenerated catalyst stream by heat exchange with the spent catalyst stream to provide the cooled regenerated catalyst stream and a heated spent catalyst stream. An embodiment of the disclosure is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising passing the cooled regenerated catalyst stream to the reactor and passing the heated spent catalyst stream to the regenerator. An embodiment of the disclosure is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising bypassing a portion of the hot regenerated catalyst stream around the heat exchange and/or bypassing a portion of the spent catalyst stream around the heat exchange. An embodiment of the disclosure is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising cooling the hot regenerated catalyst stream by mixing the hot regenerated catalyst stream with a cooled catalyst stream to provide the cooled regenerated catalyst stream. An embodiment of the disclosure is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph further comprising separating a recycle catalyst stream from the spent catalyst and cooling the recycle catalyst stream to provide the cooled catalyst stream. An embodiment of the disclosure is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph wherein contacting the reactant stream with the cooled regenerated catalyst stream produces an endothermic reaction. An embodiment of the disclosure is one, any or all of prior embodiments in this paragraph up through the first embodiment in this paragraph, wherein the catalyst comprises gallium.

A second embodiment of the present disclosure is a process for contacting a reactant stream with a regenerated catalyst, the process comprising: charging a reactant stream to a reactor; contacting the reactant stream with a cooled regenerated catalyst stream to produce a product gas stream and a spent catalyst; passing the first spent catalyst stream to a regenerator and optionally returning the second spent catalyst stream to the contacting step; regenerating the spent catalyst stream by combustion in the regenerator to provide a regenerated catalyst stream and a flue gas stream; and cooling the regenerated catalyst stream or the second spent catalyst stream to provide the cooled regenerated catalyst stream. An embodiment of the disclosure is one, any or all of prior embodiments in this paragraph up through the second embodiment in this paragraph wherein the first spent catalyst stream and the regenerated catalyst stream are mixed to provide the cooled catalyst stream.

A third embodiment of the present disclosure is an apparatus comprising a regenerator for regenerating a catalyst; a regenerated catalyst conduit in downstream communication with the regenerator for transferring regenerated catalyst from the regenerator; a catalyst cooler in downstream communication with the regenerated catalyst conduit; a cooled catalyst conduit in downstream communication with the catalyst cooler; and a reactor in downstream communication with the cooled catalyst conduit. An embodiment of the disclosure is one, any or all of prior embodiments in this paragraph up through the third embodiment in this paragraph wherein the regenerated catalyst conduit has an inlet end connected to the regenerator and an outlet end connected to the catalyst cooler. An embodiment of the disclosure is one, any or all of prior embodiments in this paragraph up through the third embodiment in this paragraph wherein the cooled catalyst conduit has an inlet end connected to the catalyst cooler and an outlet end connected to the reactor. An embodiment of the disclosure is one, any or all of prior embodiments in this paragraph up through the third embodiment in this paragraph further comprising a first side of the catalyst cooler in communication with the regenerated catalyst conduit and the cooled catalyst conduit and a second side in communication with a spent catalyst conduit and a heated catalyst conduit. An embodiment of the disclosure is one, any or all of prior embodiments in this paragraph up through the third embodiment in this paragraph wherein the catalyst cooler is in downstream communication with the spent catalyst conduit and the regenerator is in downstream communication with the heated catalyst conduit. An embodiment of the disclosure is one, any or all of prior embodiments in this paragraph up through the third embodiment in this paragraph further comprising a regenerated catalyst bypass conduit having an inlet end connected to the regenerated catalyst conduit and an outlet end connected to the cooled catalyst conduit. An embodiment of the disclosure is one, any or all of prior embodiments in this paragraph up through the third embodiment in this paragraph further comprising a spent catalyst bypass conduit having an inlet end connected to the spent catalyst conduit and an outlet end connected to the heated catalyst conduit.

Although not described in further detail, it is believed that one skilled in the art can, using the preceding description, utilize the present disclosure to its fullest extent and can readily determine the essential features of the present disclosure without departing from the spirit and scope of the invention and make various changes and modifications of the disclosure and adapt it to various uses and conditions. Accordingly, the foregoing preferred specific embodiments are to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever, and are intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

In the foregoing, all temperatures are shown in degrees celsius and all parts and percentages are by weight unless otherwise indicated.

Claims

1. A method of contacting a reactant stream with regenerated catalyst, the method comprising:

Charging a reactant stream to a reactor;

Contacting the reactant stream with a cooled regenerated catalyst stream to produce a product gas stream and a spent catalyst;

Passing the spent catalyst stream to a regenerator;

regenerating the spent catalyst stream by combustion in the regenerator to provide a hot regenerated catalyst stream and a flue gas stream;

Cooling the catalyst stream; and

The regenerated catalyst stream is transferred to the reactor.

2. The method of claim 1, further comprising cooling the hot regenerated catalyst stream by heat exchange.

3. The method of claim 2, further comprising cooling the thermally regenerated catalyst by heat exchange with air.

4. A method according to claim 3, further comprising returning heated air from the heat exchange to the regenerator.

5. The method of claim 2, further comprising cooling the hot regenerated catalyst stream by heat exchange with the spent catalyst stream to provide the cooled regenerated catalyst stream and a heated spent catalyst stream.

6. The method of claim 5, further comprising passing the cooled regenerated catalyst stream to the reactor and passing the heated spent catalyst stream to the regenerator.

7. The method of claim 5, further comprising bypassing a portion of the hot regenerated catalyst stream around the heat exchange and/or bypassing a portion of the spent catalyst stream around the heat exchange.

8. The method of claim 1, further comprising cooling the hot regenerated catalyst stream by mixing the hot regenerated catalyst stream with a cooled catalyst stream to provide the cooled regenerated catalyst stream.

9. The method of claim 8, further comprising separating a recycle catalyst stream from spent catalyst and cooling the recycle catalyst stream to provide the cooled catalyst stream.

10. A reactor apparatus comprising:

A regenerator for regenerating the catalyst;

A regenerated catalyst conduit in downstream communication with the regenerator for transferring regenerated catalyst from the regenerator;

A catalyst cooler in downstream communication with the regenerated catalyst conduit;

A cooled catalyst conduit in downstream communication with the catalyst cooler; and

A reactor in downstream communication with the cooled catalyst conduit.